文摘
In this research, the emission characteristics, morphological characteristics and size-classified elemental compositions of PM2.5 are determined experimentally before and after a fabric filter (FF) at an industrial pulverized coal boiler. Sampling and measurement of PM2.5 in situ were taken with an ELPI with a two-stage dilution sampling system. The morphological characteristics were analyzed by scanning electron microscopy. The size-classified elemental compositions were analyzed by energy-dispersive X-ray analysis and inductively coupled plasma–atomic emission spectrometry. The number size distribution of PM2.5 before the FF displays a unimodal distribution. The mass distribution of PM2.5 before the FF displays a unimodal distribution with the peak near 0.1 μm, but the mass distribution of PM2.5 after the FF shows no peak. The pulse back blowing of the FF exerts significant influence on PM2.5 number and mass concentrations after the FF, especially on the number and mass concentrations of PM0.007–0.029. There appears a penetration window in nearly 0.1–1 μm; however, the removal efficiency of PM0.007–0.029 is lowest. The pulse back blowing of the FF can reduce the removal efficiency of PM0.007–0.029 from 99.37% to 97.80%. The microstructures of super-micrometer and sub-micrometer particles are different before and after the FF; however, the ultrafine particles in 0.007–0.029 μm are nearly the same before and after the FF. The fractional mass distributions of silicon, aluminum, iron, calcium, and magnesium vary little with variation of the particle size. Cadmium, arsenic, and selenium are enriched with the particle size decreasing.